bsp_monitor: 支持全部20个币对 + 数据源切换至data_provider + Python 3.9兼容

- fetcher.py: 数据源从CCXT改为data_provider HTTP API，新增get_symbols()自动获取所有币对
- main.py: 重构为多币对架构，每个币对独立SymbolState（pivot_monitor/BSP去重/首轮抑制）
- engine.py: format_bsp_detail()支持动态币对名
- ChanPivotMonitor/Classifier: 修复Python 3.9类型注解兼容（X|None → Optional[X]）
- 首轮初始化时不推送中枢和BSP，避免启动时20条消息轰炸

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ChanPivotMonitor.py

@@ -8,6 +8,7 @@ shift / contraction / duration。
 """
 
 from collections import deque
+from typing import Optional
 from ChanPivotClassifier import ChanPivotClassifier
 
 
@@ -22,17 +23,17 @@ class ChanPivotMonitor:
     def __init__(self, window_size: int = 10):
         self._window_size = window_size
         self._duration_history: deque[int] = deque(maxlen=window_size)
-        self._current_zs_id: tuple | None = None
+        self._current_zs_id: Optional[tuple] = None
         self._current_bi_count: int = 0
         self._current_is_sure: bool = False
-        self._current_state: dict | None = None
+        self._current_state: Optional[dict] = None
         self._duration_added_for_zs: set = set()  # 已加入窗口的中枢 ID
 
     # ------------------------------------------------------------------
     # Public API
     # ------------------------------------------------------------------
 
-    def update(self, bi_zs_list: list) -> dict | None:
+    def update(self, bi_zs_list: list) -> Optional[dict]:
         """
         主入口：检测当前中枢特征变化。
 
@@ -96,7 +97,7 @@ class ChanPivotMonitor:
 
         return self._current_state
 
-    def get_current(self) -> dict | None:
+    def get_current(self) -> Optional[dict]:
         """返回当前中枢的最新特征"""
         return self._current_state